Throughout the years, a number of improvements have been made in the materials used in the manufacture of waterproof and windproof wearing apparel. Basic rubberized materials have been replaced by advanced new materials that are impermeable to the passage of water while still being breathable whereby some amount of vapor is allowed to pass through the material.
Commonly, raincoats and other similar types of garments that are used to shield the wearer from inclement weather are made from a material that has from one to three layers. When multiple material layers are used, each layer will normally serve a different purpose.
In the most basic and simplest form of a raincoat, a single layer of a plastic material such as polyethylene is used to form the entire garment. The necessary seams between the different portions of the garment are either sewn and taped or made using a heat sealing or adhesive process. Garments of this type, while being lightweight and inexpensive, are often prone to water leakage at the seams and are uncomfortable to wear for prolonged periods due to lack of breathability.
More complex types of protective wear will usually be formed out of two or three layers of bonded material. A garment of this type will typically have an inner layer made from a cotton or similar material and a waterproof outer layer made from a flexible plastic or rubber material. In recent years, breathable waterproof materials such as GORE-TEX as manufactured by the W. L. & Gore Co. have been used for the outer layer of multi-layer garments of this type. These layered garments are a considerable improvement over a basic, single layer garment. However, multi-layer garments will still often suffer from occasional leakage at their seams. In addition, multi-layer garments can be relatively heavy, are expensive to make and are usually too stiff for comfortable or prolonged wear.